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In developed countries perioperative blood transfusion requirements for red blood cell concentrates (RBC), platelet concentrates (PC), fresh frozen plasma (FFP) and stable plasma derivatives have now levelled off with more patients requiring less or no products whilst fewer patients need the larger proportion of donations. This text explores the reasons for such a development in patients undergoing cardiovascular surgery where the transfusion requirement has drastically declined in recent years. A reduced requirement of a mean of 2 RBCs is now the need per patient in most centers. Such a reduction is possible through various recent perioperative improvements: (i) thorough preoperative haematological checks in order to equip the patient for blood loss, surgical trauma and extracorporeal circulation (ECC) in which heparinized blood is pumped at high speed through an oxygenator, heat exchanger, reservoirs, tubings and connectors. (ii) Peroperative administration of inhibitors of fibrinolysis (aprotinin, epsilon-aminocaproic acid) reduce profuse haemorrhagic tendency. Successful attempts to minimise ECCs, including foamless aspiration of wound blood, refined surgical technology, tissue glue, and point-of-care laboratory testing (POCT) in the operating theatre all contribute to a reduced transfusion requirement. A substantial proportion of patients can now be operated on without ECC. New thrombelastography analysis allows for real-time monitoring of haemorrhagic/thrombogenic risk. Modern blood product quality contributes to limiting blood product usage. (iii) During the postoperative recovery phase, anaemia can be corrected by i.v.iron and recombinant human erythropoietin. Such measures allow the transfusion trigger, based on haemoglobin concentration, to be set as low as 70 g/l in suitable patients. |
